Communication method and apparatus

ABSTRACT

This application discloses a communication method and an apparatus. In a solution of this application, a base station sends, by using dedicated signaling, at least one random access parameter set to a terminal in a connected mode or an inactive mode. The base station receives a random access request of the terminal in a connected mode or an inactive mode. One of the at least one random access parameter set is used in the random access request. In this application, differentiated random access processes may be performed in different scenarios.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S Application No. 16,580/834,filed on Sep. 24, 2019, which is a continuation of InternationalApplication No. PCT/CN2018/080336, filed on Mar. 23, 2018, which claimspriority to Chinese Patent Application No. 201710185971.1, filed on Mar.24, 2017. All of the afore-mentioned patent applications are herebyincorporated by reference in their entireties.

TECHNICAL FIELD

The present invention relates to the field of wireless communicationstechnologies, and in particular, to a communication method and anapparatus.

BACKGROUND

The 5th generation mobile communications technology (5G for short)supports various types of network deployment and application types, forexample, supports an application scenario for the Internet of Vehicles,emergency communication, the Industrial Internet, and the like.Therefore, a 5G communications system requires an access capability withhigher rate experience and higher bandwidth, an information exchangecapability with lower latency and ultra-reliability, and an access andmanagement capability of a machine type communication (machine typecommunication, MTC for short) device with a larger scale and lowercosts.

In the 5G communications system, ultra-reliable and low latencycommunications (ultra-reliable and low latency communications, URLLC forshort) and enhanced mobile broadband (enhanced Mobile Broad Band, eMBBfor short) are two key application types and have different servicefeatures. For example, from the perspective of latency performance,URLLC requires that user plane latency is limited to 0.5 ms in uplinkand downlink, and eMBB requires that the user plane latency is limitedto 4 ms in uplink and downlink.

Based on the features of the 5G communications system, a new randomaccess method needs to be defined to meet the requirements of the 5Gcommunications system.

SUMMARY

Embodiments of this application provide a communication method and anapparatus, to meet a requirement of a 5G communications system.

According to a first aspect, a communication method is provided,including: sending, by a base station, a plurality of random accessparameter sets to a terminal by using a broadcast message; andreceiving, by the base station, a random access request of the terminal,where one of the plurality of random access parameter sets is used inthe random access request. In this embodiment, random access may beinitiated in a differentiated manner in different scenarios.

Optionally, the plurality of random access parameter sets are aplurality of random access parameter sets corresponding to a pluralityof random access groups, and one or more random access groups correspondto one random access parameter set. In this embodiment, a correspondingrandom access parameter set may be set based on a random access group.Further, adapted random access parameter sets may be provided indifferent scenarios (for example, a service type or a network slice)based on a correspondence between a random access group and a servicetype, a network slice, or the like.

Optionally, the plurality of random access parameter sets include arandom access parameter set corresponding to a default random accessgroup. In this embodiment, it may be ensured that one random accessgroup is matched, so as to ensure execution of random access.

Optionally, the random access parameter set further includes a randomaccess preamble sequence. The random access request includes the randomaccess preamble sequence. After the base station receives the randomaccess request sent by the terminal, the method further includes:returning, by the base station, a random access response message to theterminal, where the random access response message includes indicationinformation of an uplink resource allocated to the terminal, the uplinkresource is allocated by the base station based on a scheduling messagesize threshold value corresponding to a random access group, and therandom access group is a random access group corresponding to the randomaccess preamble sequence sent by the terminal. In this embodiment, anuplink resource may be allocated to the terminal based on a randomaccess group corresponding to the terminal, to meet differentrequirements for the uplink resource in different scenarios (the randomaccess group may be used to distinguish between scenarios).

Optionally, after the base station receives a random access request sentby the terminal, the method further includes: returning, by the basestation, the random access response to the terminal, where the randomaccess response includes a plurality of random backoff indicatorscorresponding to a plurality of random access groups. In thisembodiment, random backoff indicators corresponding to different randomaccess groups may be sent to the terminal for selection, to meet arequirement for random backoff or a random access latency or reliabilityin different scenarios (the random access group may be used todistinguish between scenarios).

According to a second aspect, a communication method is provided,including:

sending, by a base station by using dedicated signaling, at least onerandom access parameter set to a terminal in a connected mode or aninactive mode; and receiving, by the base station, a random accessrequest of the terminal in a connected mode or an inactive mode, whereone of the at least one random access parameter set is used in therandom access request, and the random access parameter set includesmonitoring start time and/or a time window size of a random accessresponse time window. In this embodiment, when the base station sends aplurality of random access parameter sets, random access may beinitiated in a differentiated manner in different scenarios; inaddition, when the base station sends one random access parameter set,because the random access parameter set includes the monitoring starttime and/or the time window size of the random access response timewindow, the monitoring start time and/or the time window size of therandom access response time window may be provided when the terminal ina connected mode or an inactive mode performs random access.

Optionally, the random access parameter set further includes a randomaccess preamble sequence. The random access request includes the randomaccess preamble sequence. After the base station receives the randomaccess request of the terminal in a connected mode or an inactive mode,the method further includes: returning, by the base station, a randomaccess response to the terminal, where the random access responseincludes indication information of an uplink resource allocated to theterminal, the uplink resource is allocated by the base station based ona scheduling message size threshold value corresponding to a randomaccess group, and the random access group is a random access groupcorresponding to the random access preamble sequence sent by theterminal. In this embodiment, an uplink resource may be allocated to theterminal based on a random access group corresponding to the terminal,to meet different requirements for the uplink resource in differentscenarios (the random access group may be used to distinguish betweenscenarios).

Optionally, after the base station receives the random access request ofthe terminal in a connected mode or an inactive mode, the method furtherincludes: returning, by the base station, the random access response tothe terminal, where the random access response includes a plurality ofrandom backoff indicators corresponding to a plurality of random accessgroups, logical channels, or logical channel groups. In this embodiment,random backoff indicators corresponding to different random accessgroups, logical channels, or logical channel groups may be sent to theterminal for selection, to meet a requirement for random backoff or arandom access latency or reliability in different scenarios (the randomaccess group, logical channel, or logical channel group may be used todistinguish between scenarios).

Optionally, the at least one random access parameter set is one randomaccess parameter set. Alternatively, the at least one random accessparameter set is a plurality of random access parameter setscorresponding to a plurality of random access groups. One or more randomaccess groups correspond to one random access parameter set.Alternatively, the at least one random access parameter set is a randomaccess parameter set corresponding to a plurality of logical channels orlogical channel groups. One or more logical channels or logical channelgroups correspond to one random access parameter set. This embodimentprovides a plurality of optional solutions, so that a random accessparameter set can correspond to a random access group, a logicalchannel, or a logical channel group, and corresponding solutions can beused for different requirements, thereby improving system flexibility.

Optionally, the random access parameter set further includes one or anycombination of the following parameters: indication information of arandom access preamble sequence; indication information of atime-frequency resource occupied by the random access preamble sequence;a timing time length of a contention resolution timer; a maximumquantity of random access times; and a scheduling message sizethreshold. This embodiment provides a plurality of solutions forparameters included in the random access parameter set, andcorresponding solutions can be used for different requirements, therebyimproving system flexibility.

According to a third aspect, a communication method is provided,including:

receiving, by a terminal, a plurality of random access parameter setssent by a base station by using a broadcast message; and

sending, by the terminal, a random access request to the base station byusing one of the plurality of random access parameter sets.

Optionally, the plurality of random access parameter sets are aplurality of random access parameter sets corresponding to a pluralityof random access groups, and one or more random access groups correspondto one random access parameter set.

Optionally, the plurality of random access parameter sets include arandom access parameter set corresponding to a default random accessgroup.

Optionally, after the sending a random access request to the basestation, the method further includes: receiving, by the terminal, arandom access response returned by the base station, where the randomaccess response includes a plurality of random backoff indicatorscorresponding to the plurality of random access groups; determining, bythe terminal, a corresponding random access group based on a randomaccess event, and selecting, based on the determined random accessgroup, a corresponding random backoff indicator from the plurality ofrandom backoff indicators corresponding to the plurality of randomaccess groups.

According to a fourth aspect, a communication method is provided,including:

receiving, by a terminal in a connected mode or an inactive mode, atleast one random access parameter set sent by a base station by usingdedicated signaling; and

sending, by the terminal in a connected mode or an inactive mode, arandom access request to the base station by using one of the at leastone random access parameter set, where the random access parameter setincludes monitoring start time and/or a time window size of a randomaccess response time window.

Optionally, the random access parameter set further includes a randomaccess preamble sequence. The random access request includes the randomaccess preamble sequence. The sending, by the terminal in a connectedmode or an inactive mode, a random access request to the base station byusing one of the at least one random access parameter set includes:determining, by the terminal in a connected mode or an inactive mode, acorresponding random access parameter set based on a logical channel ora logical channel group used for to-be-sent uplink data and/orsignaling; and sending, by the terminal in a connected mode or aninactive mode, the random access preamble sequence in the random accessparameter set to the base station based on the determined random accessparameter set.

Optionally, after the sending a random access request to the basestation, the method further includes: receiving, by the terminal, arandom access response returned by the base station, where the randomaccess response includes a plurality of random backoff indicatorscorresponding to a plurality of random access groups, logical channels,or logical channel groups; and determining, by the terminal, acorresponding random access group, logical channel, or logical channelgroup based on a random access event, and selecting a correspondingrandom backoff indicator from the plurality of random backoff indicatorsbased on the determined random access group, logical channel, or logicalchannel group.

Optionally, the at least one random access parameter set is one randomaccess parameter set. Alternatively, the at least one random accessparameter set is a plurality of random access parameter setscorresponding to a plurality of random access groups. One or more randomaccess groups correspond to one random access parameter set. Theplurality of random access groups correspond to a public land mobilenetwork PLMN accessed by the terminal in a connected mode or an inactivemode. Alternatively, the at least one random access parameter set is arandom access parameter set corresponding to a plurality of logicalchannels or logical channel groups. One or more logical channels orlogical channel groups correspond to one random access parameter set.

Optionally, the random access parameter set further includes one or anycombination of the following parameters:

indication information of a random access preamble sequence;

indication information of a time-frequency resource occupied by therandom access preamble sequence;

a timing time length of a contention resolution timer;

a maximum quantity of random access times; and

a scheduling message size threshold.

According to a fifth aspect, a base station is provided, including:

a sending module, configured to send a plurality of random accessparameter sets to a terminal by using a broadcast message; and

a receiving module, configured to receive a random access request of theterminal, where one of the plurality of random access parameter sets isused in the random access request.

Optionally, the plurality of random access parameter sets are aplurality of random access parameter sets corresponding to a pluralityof random access groups, and one or more random access groups correspondto one random access parameter set.

Optionally, the plurality of random access parameter sets include arandom access parameter set corresponding to a default random accessgroup.

Optionally, the random access parameter set further includes a randomaccess preamble sequence. The random access request includes the randomaccess preamble sequence. The sending module is further configured to:after the receiving module receives the random access request sent bythe terminal, return a random access response message to the terminal.The random access response message includes indication information of anuplink resource allocated to the terminal. The uplink resource isallocated by the base station based on a scheduling message sizethreshold value corresponding to a random access group. The randomaccess group is a random access group corresponding to the random accesspreamble sequence sent by the terminal.

Optionally, the sending module is further configured to: after thereceiving module receives the random access request sent by theterminal, return a random access response to the terminal. The randomaccess response includes a plurality of random backoff indicatorscorresponding to the plurality of random access groups.

According to a sixth aspect, a base station is provided, including:

a sending module, configured to send, by using dedicated signaling, atleast one random access parameter set to a terminal in a connected modeor an inactive mode; and

a receiving module, configured to receive a random access request of theterminal in a connected mode or an inactive mode, where one of the atleast one random access parameter set is used in the random accessrequest, and the random access parameter set includes monitoring starttime and/or a time window size of a random access response time window.

Optionally, the random access parameter set further includes a randomaccess preamble sequence. The random access request includes the randomaccess preamble sequence. The sending module is further configured to:after the receiving module receives the random access request of theterminal in a connected mode or an inactive mode, return a random accessresponse to the terminal. The random access response includes indicationinformation of an uplink resource allocated to the terminal. The uplinkresource is allocated by the base station based on a scheduling messagesize threshold value corresponding to a random access group. The randomaccess group is a random access group corresponding to the random accesspreamble sequence sent by the terminal.

Optionally, the sending module is further configured to: after thereceiving module receives the random access request of the terminal in aconnected mode or an inactive mode, return the random access response tothe terminal, where the random access response includes a plurality ofrandom backoff indicators corresponding to a plurality of random accessgroups, logical channels, or logical channel groups.

Optionally, the at least one random access parameter set is one randomaccess parameter set. Alternatively, the at least one random accessparameter set is a plurality of random access parameter setscorresponding to a plurality of random access groups. One or more randomaccess groups correspond to one random access parameter set.Alternatively, the at least one random access parameter set is a randomaccess parameter set corresponding to a plurality of logical channels orlogical channel groups. One or more logical channels or logical channelgroups correspond to one random access parameter set.

Optionally, the random access parameter set further includes one or anycombination of the following parameters:

indication information of a random access preamble sequence;

indication information of a time-frequency resource occupied by therandom access preamble sequence;

a timing time length of a contention resolution timer;

a maximum quantity of random access times; and

a scheduling message size threshold.

According to a seventh aspect, a terminal is provided, including:

a receiving module, configured to receive a plurality of random accessparameter sets sent by a base station by using a broadcast message; and

a sending module, configured to send a random access request to the basestation by using one of the plurality of random access parameter sets.

Optionally, the plurality of random access parameter sets are aplurality of random access parameter sets corresponding to a pluralityof random access groups, and one or more random access groups correspondto one random access parameter set.

Optionally, the plurality of random access parameter sets include arandom access parameter set corresponding to a default random accessgroup.

Optionally, the terminal further includes a determining module. Thereceiving module is further configured to: after the sending modulesends the random access request to the base station, receive a randomaccess response returned by the base station. The random access responseincludes a plurality of random backoff indicators corresponding to theplurality of random access groups. The determining module is configuredto: determine a corresponding random access group based on a randomaccess event, and select, based on the determined random access group, acorresponding random backoff indicator from the plurality of randombackoff indicators corresponding to the plurality of random accessgroups.

According to an eighth aspect, a terminal is provided, including:

a sending module, configured to: when the terminal is in a connectedmode or an inactive mode, receive at least one random access parameterset sent by a base station by using dedicated signaling; and a sendingmodule, configured to: when the terminal is in a connected mode or aninactive mode, send a random access request to the base station by usingone of the at least one random access parameter set, where the randomaccess parameter set includes monitoring start time and/or a time windowsize of a random access response time window.

Optionally, the terminal further includes a determining module. Therandom access parameter set further includes a random access preamblesequence. The random access request includes the random access preamblesequence. The determining module is configured to determine acorresponding random access parameter set based on a logical channel ora logical channel group used for to-be-sent uplink data and/orsignaling. The sending module is specifically configured to send therandom access preamble sequence in the random access parameter set tothe base station based on the determined random access parameter set.

Optionally, the terminal further includes a determining module. Thereceiving module is further configured to: after the sending modulesends the random access request to the base station, receive a randomaccess response returned by the base station. The random access responseincludes a plurality of random backoff indicators corresponding to aplurality of random access groups, logical channels, or logical channelgroups. The determining module is configured to: determine acorresponding random access group, logical channel, or logical channelgroup based on a random access event, and select a corresponding randombackoff indicator from the plurality of random backoff indicators basedon the determined random access group, logical channel, or logicalchannel group.

Optionally, the at least one random access parameter set is one randomaccess parameter set. Alternatively, the at least one random accessparameter set is a plurality of random access parameter setscorresponding to a plurality of random access groups. One or more randomaccess groups correspond to one random access parameter set. Theplurality of random access groups correspond to a public land mobilenetwork PLMN accessed by the terminal in a connected mode or an inactivemode. Alternatively, the at least one random access parameter set is arandom access parameter set corresponding to a plurality of logicalchannels or logical channel groups. One or more logical channels orlogical channel groups correspond to one random access parameter set.

Optionally, the random access parameter set further includes one or anycombination of the following parameters:

indication information of a random access preamble sequence;

indication information of a time-frequency resource occupied by therandom access preamble sequence;

a timing time length of a contention resolution timer; and

a maximum quantity of random access times.

According to a tenth aspect, a communication method is provided,including: sending, by a base station by using dedicated signaling, aplurality of random access parameter sets to a terminal in a connectedmode or an inactive mode; and receiving, by the base station, a randomaccess request of the terminal in a connected mode or an inactive mode,where one of the plurality of random access parameter sets is used inthe random access request.

According to an eleventh aspect, a communication method is provided,including: receiving, by a terminal in a connected mode or an inactivemode, a plurality of random access parameter sets sent by a base stationby using dedicated signaling; and sending, by the terminal in aconnected mode or an inactive mode, a random access request to the basestation by using one of the plurality of random access parameter sets.

Optionally, in any one of the method and the optional implementation ofthe method provided in the first aspect to the eleventh aspect, themethod further includes: sending, by the base station, configurationinformation of a random access group to the terminal, where the randomaccess group is configured by a core network device. Further, one randomaccess group corresponds to at least one of a public land mobile networkPLMN, a service type, a network slice, an application type, and anaccess type. Optionally, the configuration information of the randomaccess group includes at least one of a PLMN indication, a service typeindication, a network slice indication, an application type indication,and an access type indication.

Optionally, in any one of the method and the optional implementation ofthe method provided in the first aspect to the eleventh aspect, therandom access parameter set includes one or any combination of thefollowing parameters:

indication information of a random access preamble sequence;

indication information of a time-frequency resource occupied by therandom access preamble sequence;

monitoring start time and/or a time window size of a random accessresponse time window;

a timing time length of a contention resolution timer;

a maximum quantity of random access times; and

a scheduling message size threshold.

Optionally, the random access parameter set further includes a randombackoff indicator.

According to a twelfth aspect, a base station is provided. The basestation includes a memory and a processor. The memory is configured tostore program code that needs to be executed by the processor. Acommunications interface is configured to communicate with a terminal.The processor is configured to execute the program code stored in thememory, and is specifically configured to perform the method in any oneof the first aspect, the second aspect, and the tenth aspect.

According to a thirteenth aspect, a terminal is provided. The basestation includes a memory and a processor. The memory is configured tostore program code that needs to be executed by the processor. Acommunications interface is configured to communicate with a basestation. The processor is configured to execute the program code storedin the memory, and is specifically configured to perform the method inany one of the third aspect, the fourth aspect, and the twelfth aspect.

According to a fourteenth aspect, a computer readable storage medium isprovided, and is configured to store a computer software instructionused to perform a function of any one of the designs of the first aspector the second aspect. The computer software instruction includes aprogram designed for performing the method in any one of the designs ofthe first aspect, the second aspect, or the tenth aspect.

According to a fifteenth aspect, a computer readable storage medium isprovided, and is configured to store a computer software instructionused to perform a function of any one of the designs of the thirdaspect, the fourth aspect, or the eleventh aspect. The computer softwareinstruction includes a program designed for performing the method in anyone of the designs of the third aspect or the fourth aspect.

In the embodiments of this application, the base station may send aplurality of random access parameter sets to the terminal. Whenperforming random access, the terminal may perform random access basedon one of the plurality of random access parameter sets, and may performdifferentiated random access processes in different scenarios.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows an example of a schematic diagram of a 5G networkarchitecture;

FIG. 2 shows an example of a schematic diagram of a registration areaupdate procedure according to an embodiment of this application;

FIG. 3 shows an example of a schematic diagram of a random accessprocedure according to an embodiment of this application;

FIG. 4 shows an example of an implementation process of S302 in FIG. 3;

FIG. 5 shows an example of a schematic structural diagram of a mediaaccess control-control element (Media Access Control-Control Element,MAC CE for short) according to an embodiment of this application;

FIG. 6 shows an example of a schematic diagram of a random accessprocedure according to another embodiment of this application;

FIG. 7 and FIG. 8 separately show an example of a schematic structuraldiagram of a base station according to an embodiment of thisapplication;

FIG. 9 and FIG. 10 separately show an example of a schematic structuraldiagram of a terminal according to an embodiment of this application;

FIG. 11 shows an example of a schematic structural diagram of a basestation according to another embodiment of this application; and

FIG. 12 shows an example of a schematic structural diagram of a terminalaccording to another embodiment of this application.

DESCRIPTION OF EMBODIMENTS

FIG. 1 shows an example of a schematic diagram of a 5G networkarchitecture. As shown in the figure, the network architecture mayinclude a base station, a core network device, and a terminal. The corenetwork device is a 5G core network device, and the base station is anew radio base station (New Radio base station) or an evolved long termevolution (long term evolution, LTE for short) base station (namely, aneLTE base station). The terminal may communicate with the core networkdevice by using the base station. For example, the terminal may be amobile phone (or referred to as a “cellular” phone) or a computer thathas a mobile terminal. For example, the terminal may alternatively be aportable, pocket-size, handheld, computer built-in or in-vehicle mobileapparatus, which exchanges voices and/or data with a radio accessnetwork. The terminal in embodiments of this application mayalternatively be a D2D (device to device, device to device) terminal oran M2M (machine to machine, machine to machine) terminal.

Network slicing is a key technology of a 5G system. One network sliceincludes all resources that can meet a service requirement.Specifically, the network slice includes network functions of a controlplane and a user plane of a core network, a resource of the core network(for example, a computing resource, a storage resource, and a networkresource), and an air interface access network.

One terminal can simultaneously support and access a plurality ofnetwork slices. When the terminal initially accesses a network orperforms tracking area update (tracking area update, TAU for short), theterminal provides slice selection assistance information (network sliceselection assistance information, NSSAI), so that the network selects aslice instance of a radio access network (Radio Access Network, RAN forshort) part and a slice instance of a core network part. The NSSAIincludes one piece of or a group of S-NSSAI (single management-networkslice selection assistance information, session management-sliceselection assistance information), and one piece of S-NSSAI may be usedto select a specific network slice.

Each piece of S-NSSAI may include the following content: a slice/servicetype (slice/service type, SST for short), pointing to a specific featureand service type of a slice. Optionally, each piece of S-NSSAI mayfurther include a slice differentiator (slice differentiator, SD forshort). As a supplement of the SST, the SD may be further used todistinguish between a plurality of network slice instances that meet asame SST.

In the 5G communications system, the terminal has three modes: an idlemode, a connected mode, and an inactive mode. There is no radio accesscontrol (radio resource control, RRC for short) connection between aterminal in an idle mode and the base station, there is an RRCconnection between the base station and a terminal in a connected modeand an active mode, and the RRC connection between the terminal in anactive mode and the base station is suspended.

All random access time in an existing LTE system is based on a set ofrandom access parameters. This cannot meet different requirements of aplurality of service types, a plurality of network slices, and aplurality of access types in the 5G system. To meet differentrequirements of the plurality of service types, the plurality of networkslices, and the plurality of access types in the 5G system, a randomaccess solution of a random access group based on a service type, anetwork slice, an access requirement, a signaling level, and the likefor a new radio random access process is proposed in the embodiments ofthis application, so that a network side can flexibly allocate an airinterface resource in the random access process of the terminal based ondifferent random access groups, thereby improving user experience,meeting a new transmission characteristic in new radio, and ensuringsystem flexibility, differentiation, and reliability in the randomaccess solution.

In the embodiments of this application, a plurality of random accessgroups are defined. The random access group may be classified based on aservice type, a slice type, a connection type, and the like. Todifferentiate different service types, slice types, and connection typesin the random access process, a random access parameter set for eachrandom access group is defined in the embodiments of this application.

A communication method provided in the embodiments of this applicationmay relate to a random access parameter configuration step and a randomaccess request initiation step, and may be implemented based on thenetwork architecture shown in FIG. 1. Certainly, the communicationmethod may also be implemented based on an evolved network architecture.The following describes in detail the embodiments of this applicationwith reference to accompanying drawings.

Generally, the embodiments of this application provide the followingsolutions.

Solution 1: The base station sends a plurality of random accessparameter sets to the terminal by using a broadcast message. “Aplurality of” means two or more. The terminal may send a random accessrequest to the base station by using one of the plurality of randomaccess parameter sets, to perform a random access process with the basestation. One or more random access groups correspond to one randomaccess parameter set. Optionally, the plurality of random accessparameter sets include a random access parameter set corresponding to adefault random access group.

The solution may be applicable to the terminal in an idle mode, theterminal in a connected mode, or the terminal in an inactive mode.Specifically, the terminal in any one of an idle mode, a connected mode,and an inactive mode may receive the plurality of random accessparameter sets sent by the base station by using the broadcast message.When needing to perform random access, the terminal in any one of anidle mode, a connected mode, and an inactive mode may initiate a randomaccess process by using one of the plurality of random access parametersets.

Solution 2: The base station sends, by using dedicated signaling, atleast one random access parameter set to the terminal in a connectedmode or an inactive mode. When the “at least one random access parameterset” refers to a plurality of random access parameter sets, theplurality of random access parameter sets may correspond to a pluralityof random access groups. One or more random access groups correspond toone random access parameter set. The plurality of random accessparameter sets may alternatively correspond to a plurality of logicalchannels or logical channel groups. One logical channel or logicalchannel group corresponds to one random access parameter set, or aplurality of logical channels or logical channel groups correspond toone random access parameter set.

The solution may be applicable to both the terminal in a connected modeand the terminal an inactive mode. When the “at least one random accessparameter set” refers to one random access parameter set, the terminalin a connected mode or an inactive mode may initiate a random accessprocess by using the random access parameter set. When the “at least onerandom access parameter set” refers to a plurality of random accessparameter sets, the terminal in a connected mode or an inactive mode mayinitiate a random access process based on one of the plurality of randomaccess parameter sets.

Solution 3: The solution 1 and the solution 2 are combined.Specifically, the base station may send a plurality of random accessparameter sets to the terminal by using a broadcast message, or maysend, by using dedicated signaling, at least one random access parameterset to the terminal in a connected mode or an inactive mode. The randomaccess parameter set sent by the base station by using the broadcastmessage is used by the terminal in an idle mode to initiate randomaccess, and the random access parameter set sent by the base station byusing the dedicated signaling is used by the terminal in a connectedmode or an inactive mode to initiate random access.

In the embodiments of this application, a random access group may beclassified based on a factor such as a public land mobile network(Public Land Mobile Network, PLMN for short) to which the terminalrequests to access, a requested service type, a used network slice, anda used access type. Optionally, the service type may include a shortmessage service (short messaging service, SMS for short), an IPmultimedia subsystem (IP multimedia subsystem, IMS for short) voiceservice, an IMS video service, and the like. Optionally, the access typemay include emergency service access, high-priority access, mobileterminated access, non-access stratum signaling, access stratumsignaling, and the like.

Optionally, one random access group may correspond to at least one ofthe PLMN, the service type, the network slice, an application type, andthe access type. Correspondingly, configuration information of onerandom access group includes at least one of a PLMN identifier, aservice type identifier, a network slice identifier, an application typeidentifier, and an access type identifier. The network slice identifiermay be the S-NSSAI (including the SST and the SD). Table 1 shows anexample of configuration information of a random access group.

TABLE 1 Configuration information of a random access group Grouping PLMNNetwork slice Application index identifier identifier type identifierService type . . . 0 1 * 5 MT (downlink . . . service trigger) 1 2 * *Emergency call . . . 2 * * * MO (uplink . . . service trigger) 3 * 3 * *. . .

Table 1 shows configuration information of a random access group 0, arandom access group 1, a random access group 2, and a random accessgroup 3. Configuration information of each random access group mayinclude a PLMN identifier, a network slice identifier, an applicationtype identifier, a service type identifier, and the like. A symbol “*”is a wildcard character, representing any matching. For example, in theconfiguration information of the random access group 2, the PLMNidentifier is represented as *, indicating that any PLMN network may beused. Optionally, in configuration information of a default randomaccess group, entries such as the PLMN identifier, the network sliceidentifier, and the service type identifier may be represented by usinga wildcard character. A priority of the default random access group isthe lowest. Only when the terminal cannot match another random accessgroup other than the default random access group based on a randomaccess event, the terminal selects the default random access group.

It can be learned from Table 1 that a unified random access group formatis defined. The format may be used to define various possibleapplication scenarios. At least one or more combinations of the PLMNidentifier, the service type identifier, the network slice identifier,the application type identifier, and the access type identifier may beused to distinguish between different random access groups.

A random access group may be configured by the core network device andsent to the base station. The base station may send configurationinformation of the random access group to the terminal. In a process ofaccessing a network (that is, a network registration process), a servicerequest (service request) process, a protocol data unit (protocol dataunit, PDU for short) session establishment process, or a registration(registration) update process, the configuration information of therandom access group may be sent by the core network device to theterminal by using the base station.

FIG. 2 shows an example of a registration area update procedure of aterminal. In the procedure, a base station sends configurationinformation of a random access group to the terminal. As shown in thefigure, the procedure may include the following steps:

S201 and S202. The terminal sends a registration area update requestmessage to the base station, and the base station sends a registrationarea update request to a core network device.

S203. The core network device sends a registration area update responsemessage to the base station, where the response message includes theconfiguration information of the random access group.

S204. The base station sends the registration area update responsemessage to the terminal, where the response message includes theconfiguration information of the random access group.

S205 and S206. The terminal sends a registration area update completemessage to the base station, and the base station sends the registrationarea update complete message to the core network device.

In this embodiment of this application, a random access parameter setmay include one or any combination of the following parameters.

Indication information of a random access preamble sequence: The randomaccess preamble sequence is also referred to as a physical random accesschannel (Physical random access channel, PRACH for short) sequence.Indication information of a random access preamble sequence may be anindex of a random access preamble sequence, or may be displacement of arandom access preamble root sequence with respect to a random accesspreamble sequence. Optionally, indication information of a random accesspreamble sequence in different random access parameter sets isdifferent. In this case, different random access groups correspond todifferent random access preamble sequences. When a plurality ofterminals initiate random access, because the plurality of terminals maycorrespond to different random access groups, different random accesspreamble sequences may be used to send an Msg1 (namely, a first messagein a random access process), so that impact of an Msg1 storm caused by arandom access event on another random access event can be alleviated oreven eliminated. In addition, service types, network handovers,application types, and the like can be distinguished on a network sidein a random access phase (especially an initial random access phase),for example, whether a service initiated by the terminal is a URLLCservice or an eMBB service, thereby providing a basis for processing andoperation on the network side.

Optionally, 64 random access preamble sequences may be available in eachcell. The preamble sequences are classified into two parts. One part isused for contention-based random access, and the other part is used forthe non-contention based random access. The contention-based randomaccess preamble sequence may be further classified into group A andgroup B.

Indication information of a time-frequency resource occupied by a randomaccess preamble sequence: used to indicate the time-frequency resourceoccupied by the random access preamble sequence. Optionally, indicationinformation of a time-frequency resource of a random access preamblesequence in different random access parameter sets is different. In thisway, different random access groups correspond to different randomaccess preamble time-frequency resources. When a plurality of terminalsinitiate random access, because the plurality of terminals maycorrespond to different random access groups, different random accesspreamble sequence time-frequency resources may be used to send an Msg1message, so that impact of an Msg1 storm caused by a random access eventon another random access event can be alleviated or even eliminated.

Monitoring start time and/or a time window size of a random accessresponse time window: The random access response time window is used bythe terminal to listen to a random access response message (namely, anMsg2 in a random access process) sent by the base station. After sendinga random access preamble sequence (by using the Msg1) to the basestation, the terminal may start the random access response time window,and listen to, in the time window, a random access response messagereturned by the base station. Optionally, the random access responsetime window may start from several subframes after a subframe in whichthe terminal sends the random access preamble sequence (denoted as thesubframe for sending the random access preamble sequence+ the monitoringstart time of the time window), and the time window size of the timewindow is continued. The time window size may be several subframes, andis represented by using a ra-RsponseWindowSize parameter of the timewindow.

One or more random access groups may correspond to one random accessparameter set, and the random access group may be classified from theperspective of a service type, a network slice, and the like. In view ofthis, different random access response time window parameters may be setbased on characteristics and requirements of different service typesand/or different network slices. For example, short monitoring starttime or a short time window size is set for a service of a URLLC type,so that a terminal that performs the service of this type can access anetwork quickly. Table 2 shows an example of monitoring start timeand/or a time window size of a random access response time window in arandom access parameter set corresponding to different random accessgroups.

TABLE 2 Random access response time window parameters in a random accessparameter set corresponding to different random access groups RandomMonitoring Ra-Rsponse access start time WindowSize group (TTI or ms)(TTI or ms) 0 2 4 1 3 6

In Table 2, a service type corresponding to a random access group 0 isURLLC, and a service type corresponding to a random access group 1 iseMBB. Because a latency requirement of a URLLC service is higher thanthat of an eMBB service, monitoring start time of a random accessresponse time window in a random access parameter set corresponding tothe random access group 0 is relatively short.

A timing time length of a contention resolution timer: The time lengthmay be in a unit of ms, or may be in a unit of transmission timeinterval (transmission time interval, TTI for short). The contentionresolution timer is used by the terminal to listen to, within timingtime of the timer, a contention resolution message returned by the basestation (namely, an Msg4 in a random access process). After sending theMsg3 to the base station, the terminal may start the timer, and listento, within the timing time of the timer, the contention resolutionmessage returned by the base station. Optionally, different timing timelengths of the contention resolution timer may be set for differentrandom access groups. For example, for a random access groupcorresponding to a URLLC type service, a relatively short time lengthmay be set, to meet a latency requirement of the service of this type.

A maximum quantity of random access times: If a random access process ofthe terminal fails, the random access process may be re-initiated whenthe maximum quantity of random access times is not reached. Optionally,different maximum quantities of random access times may be set fordifferent random access groups. For example, for the random access groupcorresponding to the URLLC type service, a relatively large maximumquantity of random access times may be set, to meet a reliabilityrequirement of the service of this type.

A scheduling message (Msg3) size threshold: Different random accessgroups may correspond to different scheduling message (Msg3) sizethresholds.

Further, a random access parameter set may further include a randombackoff indicator, used to indicate a random backoff time length. Whenthe terminal needs to re-initiate random access due to a random accessfailure, the terminal may randomly select a moment from a correspondingtime interval based on the random backoff time length indicated by therandom backoff indicator, to send the random access preamble sequence.Optionally, values of random backoff indicators corresponding todifferent random access groups may be different. For example, for arandom access group corresponding to a service type with a high latencyrequirement, a relatively short random backoff time length is set forthe random access group, so that a random access process is re-initiatedas soon as possible when random access fails.

Further, a random access parameter set may further include an Msg3threshold, where the Msg3 threshold is used to indicate random accesspreamble sequence groups (group A and group B) used when the terminalselects the Msg1. Optionally, values of Msg3 thresholds corresponding todifferent random access groups may be different. For example, for arandom access group corresponding to an eMBB service type with a highthroughput requirement, a relatively large Msg3 threshold is set for therandom access group, so that the base station allocates a relativelylarge uplink resource when allocating an uplink resource correspondingto the Msg3.

The foregoing is only an example of a random access parameter includedin a random access parameter set. The foregoing listed random parametersmay alternatively be replaced with other random parameters, or anotherrandom access parameter may be included in addition to the foregoinglisted random access parameters. For example, the random accessparameter set may further include a quantity of random access preamblesequences, grouping information of a random access preamble sequence(the contention-based random access preamble sequence may be classifiedinto group A and group B), and the like. The grouping information of therandom access preamble sequence may be indication information of thegroup A or indication information of the group B.

The random access parameter included in the random access parameter setmay be organized by using a plurality of data structures. For example, arandom access parameter included in a random access parameter set may bedivided into three parameter subsets.

Parameter subset 1: also referred to as a random access channel commonconfiguration (RACH-Config Common) subset. RACH-Config Common mayinclude one or more of the following parameters: a quantity of randomaccess preamble sequences, grouping information of a random accesspreamble sequence, and a scheduling message (Msg3) size threshold value.The foregoing is merely an example, and RACH-Config Common may furtherinclude another parameter.

Parameter subset 2: also referred to as a PRACH system configuration(PRACH-ConfigSlB) subset. PRACH-ConfigSlB may include one or more of thefollowing parameters: a random access preamble root sequence, and PRACHtime-frequency resource information. The PRACH time-frequency resourceinformation is used to indicate a time-frequency resource occupied by arandom access preamble sequence. The foregoing is merely an example, andPRACH-ConfigSlB may further include another parameter.

Parameter subset 3: also referred to as a timer and a time windowsubset. The subset may include one or more of the following parameters:a random access response window size (ra-RsponseWindowSize), a randombackoff indicator (Backoff indicator), and a contention resolution timer(mac-ContentionResolutionTimer) timing time length. The foregoing ismerely an example, and the subset may further include another parameter.

Table 3 shows, in a list manner, an example of three random accessparameter sets sent by the base station by using a broadcast message.

TABLE 3 A plurality of random access parameter sets sent by a basestation by using broadcast message Random RACH- Timer access ConfigPRACH- and time group Common ConfigSIB window 0 Parameter subsetParameter subset Parameter subset 1 Parameter subset Parameter subsetParameter subset 2 Parameter subset Parameter subset Parameter subset

Table 3 shows three random access parameter sets corresponding to arandom access group 0, a random access group 1, and a random accessgroup 2. Each random access parameter set includes a RACH-Config Commonparameter subset, a PRACH-ConfigSlB parameter subset, and a timer andtime window parameter subset.

Parameters included in different random access parameter sets may havethe following cases: Parameter values of some parameters are the same,or parameter values of all parameters are the same, or parameter valuesof all parameters are different. Therefore, different random accessparameter sets have a plurality of representation manners. Severalpossible cases are listed below.

Case 1: For different random access parameter sets, random accesspreamble sequences included in the random access parameter sets aredifferent and belong to different random access preamble sequencegroups. However, time-frequency resources occupied by the random accesspreamble sequences are the same, and Msg3 size threshold values indifferent random access parameter sets are also different.

Case 2: For different random access parameter sets, random accesspreamble sequences included in the random access parameter sets are thesame and belong to a same random access preamble sequence group.However, time-frequency resources occupied by the random access preamblesequences are different, and Msg3 size threshold values in differentrandom access parameter sets are the same.

Case 3: For different random access parameter sets, random accesspreamble sequences included in the random access parameter sets aredifferent and belong to different random access preamble sequencegroups. Time-frequency resources occupied by the random access preamblesequences are also different, and Msg3 size threshold values indifferent random access parameter sets are also different.

A parameter type included in a random access parameter set correspondingto a logical channel or logical channel group is similar to that in theforegoing embodiment. Parameter values in random access parameter setscorresponding to different logical channels or logical channel groupsmay be the same or may be different. Based on different priorities ofthe logical channels or the logical channel groups, different values maybe set for parameters in random access parameter sets corresponding tological channels or logical channel groups with different priorities. Alogical channel 1 and a logical channel 2 are used as an example. Arandom parameter set corresponding to the logical channel 1 is a set A.A random access parameter set corresponding to the logical channel 2 isa set B. A priority of the logical channel 1 is higher than a priorityof the logical channel 2. In this case, random access parameters in theset A and the set B may include one or a combination of the followingfeatures.

In the set A and the set B, random access preamble sequences aredifferent and/or time-frequency resources occupied by the random accesspreamble sequences are different. In this case, the base station maydetermine a corresponding logical channel or logical channel group basedon a received random access preamble sequence and/or a time-frequencyresource occupied by the sequence, so as to provide a basis for asubsequent operation.

In the set A and the set B, monitoring start time and/or time windowsizes of random access response time windows are different, andmonitoring start time and duration of a random access response timewindow in the set A are relatively short. This can ensure that data thatuses a logical channel or a logical channel group with a high prioritycan be transmitted as soon as possible.

In the set A and the set B, maximum quantities of random access timesare different, and a maximum quantity of random access times in the setA is relatively large. In this case, an access success rate of ahigh-priority logical channel or logical channel group can be ensured.

In the set A and the set B, timing time lengths of contention resolutiontimers are different, and a timing time length of a contentionresolution timer in the set A is relatively long. In this case, for ahigh-priority logical channel or logical channel group, it is ensuredthat a contention resolution message can be received as much aspossible.

Optionally, values of random backoff indicators corresponding todifferent logical channels or logical channel groups are different. Forexample, random backoff time corresponding to a high-priority logicalchannel or logical channel group is relatively short (a smaller valuemay indicate earlier performing of random backoff). In this case, randomaccess may be performed as soon as possible for the high-prioritylogical channel or logical channel group.

In this embodiment of this application, the foregoing random accessparameter set may be sent by the base station to the terminal, so thatthe random access parameter set is used by the terminal during randomaccess. A random access parameter configuration process and a randomaccess process provided in the embodiments of this application aredescribed in detail below with reference to the accompanying drawings.

FIG. 3 shows an example of a communication procedure according to anembodiment of this application. The procedure shown in FIG. 3 may beapplicable to the scenario described in the solution 1. This procedureis also applicable to the scenario described in the solution 3. In thescenario, a terminal in an idle mode initiates a random access processby using one of a plurality random access parameter sets sent by a basestation by using a broadcast message.

As shown in the figure, the procedure may include the following steps.

S301. A base station sends a plurality of random access parameter setsto a terminal by using a broadcast message.

In this step, the base station sends the plurality of random accessparameter sets by using the broadcast message. Therefore, the terminalmay receive the plurality of random access parameter sets regardless ofwhether the terminal is in an idle mode, a connected mode, or aninactive mode. After receiving the plurality of random access parametersets sent by the base station, the terminal may store the plurality ofrandom access parameter sets in the terminal.

The plurality of random access parameter sets sent by the base stationmay be random access parameter sets corresponding to a plurality ofrandom access groups, and one or more random access groups maycorrespond to one random access parameter set. Optionally, the pluralityof random access parameter sets include a random access parameter setcorresponding to a default random access group.

S302. The terminal sends a random access request to the base station byusing one group of the plurality of random access parameter sets, totrigger a random access process.

In this step, the terminal may initiate the random access process basedon one of the plurality of random access parameter sets regardless ofwhether the terminal is in an idle mode, a connected mode, or aninactive mode. For example, when the terminal is in an idle mode, ifthere is uplink data and/or signaling to be sent, the random accessprocess may be initiated by using one of the plurality of random accessparameter sets. For another example, when the terminal is in a connectedmode, if there is uplink data and/or signaling to be sent, but uplink isout of synchronization, the random access process may be initiated byusing one of the plurality of random access parameter sets. Theforegoing merely gives an example of some reasons for triggering randomaccess. Certainly, the random access process may be triggered foranother reason, for example, when the terminal in a connected modeperforms handover or terminal positioning. Examples are not given one byone herein.

That the terminal sends the random access request and triggers therandom access process based on the random access request in S302 in FIG.3 includes a signaling interaction process between the terminal and thebase station. FIG. 4 shows an example of an implementation process ofS302 in FIG. 3. As shown in FIG. 4, the process may include thefollowing steps.

S401. A terminal selects, based on a random access event that triggers arandom access process, one random access parameter set from a pluralityof random access parameter sets sent by a base station.

The random access event may trigger the random access process. There maybe various random access events to describe different random accesstriggering reasons, scenarios, and the like. For example, the randomaccess event may include:

-   -   (1) initial access;    -   (2) RRC connection re-establishment;    -   (3) cell handover;    -   (4) downlink data of a terminal in a connected mode arrives but        uplink is out of synchronization;

(5) uplink data of the terminal in a connected mode arrives but uplinkis out of synchronization; and

-   -   (6) the terminal in a connected mode performs positioning.

In this embodiment of this application, the random access event may befurther refined, so that the terminal selects a corresponding randomaccess parameter set based on a more refined scenario or reason. Forexample, the further refined random access event may be described asfollows.

(1) Initial access

The random access event may be further classified from the perspectiveof a service type, a network slice, a PLMN, an application type, and anaccess type. A classification perspective of the random access event issimilar to a classification perspective of a random access group.

(2) The uplink data of the terminal in a connected mode arrives butuplink is out of synchronization.

The random access event may be further classified from the perspectiveof a service type, a network slice, a PLMN, an application type, and anaccess type. A classification perspective of the random access event issimilar to a classification perspective of a random access group.

S402. The terminal sends a random access preamble sequence (for example,an Msg1 shown in the figure) to the base station, this step correspondsto S302 in FIG. 3, and the random access preamble sequence sent in S402may be understood as a special case or an example of the random accessrequest sent in S302.

In this step, if the random access parameter set selected by theterminal includes indication information of the random access preamblesequence, the terminal may send a corresponding random access preamblesequence based on the indication information of the random accesspreamble sequence. If the random access parameter set selected by theterminal includes time-frequency resource indication information of therandom access preamble sequence, the terminal may send the random accesspreamble sequence by using a corresponding time-frequency resource.

Further, if the random access parameter set selected by the terminalincludes monitoring start time and/or a time window size of a randomaccess response time window, the terminal may listen on a physicaldownlink control channel (physical downlink control channel, PDCCH forshort) in a corresponding time period (that is, the random accessresponse time window) after sending the random access preamble sequence,to receive a random access response message sent by the base station.

S403. After receiving the random access preamble sequence (Msg1) sent bythe terminal, the base station allocates an uplink resource to theterminal, and returns a random access response message (for example, anMsg2 in the figure) to the terminal, where the random access responsemessage carries indication information of the uplink resource allocatedto the terminal and the random access preamble sequence sent by theterminal in S402.

In this step, when the base station determines a corresponding randomaccess group based on the received random access preamble sequenceand/or a time-frequency resource occupied by the random access preamblesequence, the base station may allocate an uplink resource in acorresponding size to the terminal based on a scheduling message (Msg3)size threshold value corresponding to the determined random accessgroup, so that the uplink resource allocated to the terminal can be usedto transmit an Msg3 whose size does not exceed the size threshold value.One or more random access groups may correspond to a size thresholdvalue of one Msg3. Optionally, size threshold values of an Msg3corresponding to different random access groups may be different, so asto meet requirements of the Msg3 message in different cases. Forexample, a corresponding random access group set is set for differentaccess types (access of a terminal in an inactive mode, initial access,and the like). For a random access group corresponding to the type ofaccess of the terminal in an inactive mode, a size threshold value of anMsg3 corresponding to the random access group is relatively large, so asto meet a requirement that the terminal in an inactive mode needs tocarry a Resume ID or even data in the Msg3. For a random access groupcorresponding to the initial access type, a size threshold value of anMsg3 corresponding to the random access group is relatively small, so asto meet a requirement that an initial random access terminal carries anS-TMSI or a random number in the Msg3 message. In this way, if the basestation determines that the access type of the terminal is access of aterminal in an inactive mode, a relatively large uplink resource may beallocated to the terminal. If the base station determines that theaccess type of the terminal is initial access, a relatively small uplinktransmission resource may be allocated to the terminal.

If random access preamble sequences corresponding to different randomaccess groups are different, time-frequency resources occupied by therandom access preamble sequences are different, or combinations of arandom access preamble sequence and a time-frequency resource occupiedby the random access preamble sequence are different, the base stationmay determine a corresponding random access group based on the receivedMsg1.

S404. After the terminal receives the random access response message(Msg2), if the message includes the random access preamble sequence sentby the terminal in S402, the terminal sends a scheduling message (anMsg3 in the figure) based on the uplink resource allocated by the basestation.

In this step, after sending the Msg3, the terminal may start acontention resolution timer, and listen on the PDCCH within timing timeof the contention resolution timer, to receive a contention resolutionmessage (Msg4) returned by the base station. Further, if the terminalperforms a hybrid automatic repeat request (hybrid automatic repeatrequest, HARQ for short) for the Msg3, the timer is reset.

S405. After receiving the scheduling message (Msg3) sent by theterminal, the base station returns a contention resolution message (anMsg4 in the figure) to the terminal, and if the Msg4 indicates that aconflict is resolved successfully, the terminal determines that therandom access process is successful.

Optionally, if the base station cannot access the terminal afterreceiving the Msg1 sent by the terminal, a random backoff indicator maybe included in the random access response message returned to theterminal. If the base station may determine a corresponding randomaccess group based on a received random access preamble sequence and/ora time-frequency resource occupied by the random access preamblesequence, a random backoff indicator corresponding to the random accessgroup may be carried in the random access response message. If the basestation cannot determine a corresponding random access group based on areceived random access preamble sequence and/or a time-frequencyresource occupied by the random access preamble sequence, a randombackoff indicator corresponding to each random access group may becarried in the random access response message. Optionally, one or morerandom access groups correspond to one random backoff indicator.

In an embodiment, a new MAC CE format in an Msg2 is defined to carry aplurality of random backoff indicators corresponding to a plurality ofrandom access groups. FIG. 5 shows an example of a MAC CE that carriesrandom backoff indicators corresponding to five random access groups.BI-0 to BI-4 in the MAC CE are random backoff indicators respectivelycorresponding to a random access group 0 to a random access group 4.Optionally, quantities of bits occupied by the random backoff indicatorsare the same. A correspondence between a random backoff indicatorincluded in the MAC CE and a random access group may be stipulated, forexample, five random access groups are used as an example. In this case,the random backoff indicators included in the MAC CE sequentiallycorrespond to the five random access groups in a stipulated order. Acorrespondence is shown in FIG. 5.

In another embodiment, the MAC CE in the Msg2 carries one random backoffindicator. A random backoff indicator (random backoff time)corresponding to each random access group may be obtained throughcalculation in the following manner: using the random backoff indicatorincluded in the MAC CE as a reference value, and multiplying a randomaccess time coefficient corresponding to the random access group toobtain the random backoff time corresponding to the random access group.A value range of the random access time coefficient may be set to (0,1), in other words, the random access time coefficient is greater than 0and less than 1.

Optionally, when a random access parameter set sent by a base station toa terminal includes the random backoff indicator, a random accessresponse message sent by the base station may not include the randombackoff indicator.

Further, if the Msg2 received by the terminal includes a plurality ofrandom backoff indicators or random backoff time coefficientscorresponding to random access groups, the terminal may select, based onthe random access group determined in S401, a corresponding randombackoff indicator or random backoff time coefficient from the pluralityof random backoff indicators corresponding to the random access groups,to perform a random backoff process.

In the foregoing procedure, in S405, if the Msg4 received by theterminal indicates that conflict resolution fails, the terminal maydetermine whether a maximum quantity of random access times is currentlyreached. If the maximum quantity of random access times is not reachedcurrently, the terminal may start a random backoff timer based on arandom backoff indicator, and perform random backoff, to be specific, arandom access process is re-initiated when the random backoff timerexpires. The initiated random access process may refer to S402 to S405in the foregoing procedure. If the maximum quantity of random accesstimes is currently reached, the terminal may further notify a high layerthat a random access problem occurs. The high layer may be wireless (forexample, an RRC layer).

If the random access parameter set selected by the terminal in S401includes the maximum quantity of random access times, the terminal maydetermine, based on the maximum quantity of random access times, whetherthe maximum quantity of random access times is currently reached. If therandom access parameter set does not include the maximum quantity ofrandom access times, the terminal may determine, based on a defaultmaximum quantity of random access times, whether the maximum quantity ofrandom access times is currently reached. The default maximum quantityof random access times is applicable to all random access groups.

In the foregoing procedure, after the base station sends the Msg2, ifthe terminal does not receive, within a random access response timewindow, an Msg3 returned by the base station, or receives an Msg3 butthe Msg3 does not include the random access preamble sequence sent bythe terminal in S402, the terminal determines that the current randomaccess process fails. In this case, in a solution, the terminal mayre-initiate a random access process when the maximum quantity of randomaccess times is not reached. In another solution, if the Msg2 includes arandom backoff indicator or the terminal may determine a random backoffindicator based on the received Msg2, the terminal may start the randombackoff timer based on the random backoff indicator when the maximumquantity of random backoff times is not reached. A timing length of therandom backoff timer is a random time between 0 and a time length valueindicated by the random backoff indicator. The terminal re-initiates therandom access process when the random backoff timer expires. Are-initiated random access process may refer to S402 to S405 in theforegoing procedure.

It can be learned from the foregoing procedures shown in FIG. 3 and FIG.4 that, based on the plurality of random access parameter setscorresponding to the random access groups, the terminal can select onecorresponding random access parameter set to perform random access basedon a random access group corresponding to the terminal. The randomaccess group may be classified based on a service type, a network slice,and the like. Therefore, different random access parameter sets may beset for different service types and network slices, to meet features andrequirements of corresponding service types and network slices, so thatdifferentiation between different events that trigger random access isimplemented in a random access process, and terminal experience isimproved.

FIG. 6 shows an example of a random access procedure according to anembodiment of this application. The procedure shown in FIG. 6 may beapplicable to the scenario described in the solution 2. This procedureis also applicable to the scenario described in the solution 3. In thescenario, a terminal in a connected mode or an inactive mode performs arandom access process by using one of random access parameter sets sentby a base station by using dedicated signaling.

As shown in the figure, the procedure may include the following steps.

S601. A base station sends at least one random access parameter set to aterminal in a connected mode or an inactive mode by using the dedicatedsignaling.

In this step, after the terminal completes the random access procedureand establishes an RRC connection to the base station, the base stationmay send an RRC connection reconfiguration message, and the at least onerandom access parameter set is sent to the terminal by using themessage. Optionally, the terminal returns an RRC connectionreconfiguration complete message to the base station. Certainly, thebase station may alternatively send the at least one random accessparameter set to the terminal in a connected mode or an inactive mode byusing other dedicated signaling.

The at least one random access parameter set may include the followingcases:

Case 1: A plurality of random access parameter sets corresponding torandom access groups. Optionally, the plurality of random accessparameter sets include a random access parameter set corresponding to adefault random access group. Random access groups may be classified in asame manner as that in the foregoing embodiment. Values of parameters inthe plurality of random access parameter sets sent by using thededicated signaling may be different from values of parameters in randomaccess parameter sets that correspond to random access groups and thatare sent by using a broadcast message.

Optionally, because the base station may obtain an identifier of a PLMNaccessed by the terminal, the random access parameter set sent by thebase station to the terminal by using the dedicated signaling mayinclude only a random access parameter set corresponding to the PLMN(namely, a PLMN currently accessed by the terminal). For example, theidentifier of the PLMN currently accessed by the terminal is a PLMN ID1. Table 5 shows an example of a random access group 0 and a randomaccess group 1 that are corresponding to the PLMN ID 1.

TABLE 4 Configuration information of a random access group correspondingto a same PLMN Random Network Application Service access PLMN handovertype type group identifier identifier identifier identifier . . . 0 1 35 * . . . 1 1 * * * . . . “*” in Table 5 represents a wildcardcharacter.

Case 2: A random access parameter set corresponding to a plurality oflogical channels or logical channel groups. One logical channel orlogical channel group may correspond to one random access parameter set,or a plurality of logical channels or logical channel groups maycorrespond to one random access parameter set. Parameter values inrandom access parameter sets corresponding to different logical channelsor logical channel groups may be the same or may be different.

Case 3: One random access parameter set. The random access parameter setmay be dedicated to the terminal in a connected mode or an inactive modefor random access. When the base station sends one random accessparameter set by using the dedicated signaling, the random accessparameter set includes a monitoring start time and/or a time window sizeof a random access response time window. Further, the random accessparameter set may further include another parameter, for example, mayinclude one or any combination of the following parameters: indicationinformation of a random access preamble sequence, indication informationof a time-frequency resource occupied by a random access preamblesequence, timing time length of a contention resolution timer, and amaximum quantity of random access times.

S602. The terminal in a connected mode or an inactive mode sends arandom access request to the base station based on one of the at leastone random access parameter set, to trigger a random access process.

In this step, there are a plurality of reasons for triggering theterminal in a connected mode or an inactive mode to initiate the randomaccess process. For example, when the terminal is in a connected mode,if there is uplink data and/or signaling to be sent but uplink is out ofsynchronization, the terminal may perform the random access process.

The random access process triggered in S602 in FIG. 6 includes asignaling interaction process between the terminal and the base station.S602 and signaling interaction of the triggered random access processare similar to the signaling interaction process shown in FIG. 4.

Based on the foregoing several cases in which the base station sends theat least one random access parameter set by using the dedicatedsignaling in S601, the signaling interaction process of random accessbetween the terminal and the base station may include the followingseveral cases:

Case 1: The base station sends, by using the dedicated signaling, aplurality of random access parameter sets corresponding to random accessgroups. In this case, an implementation process of a random accessprocess initiated by the terminal may be the same as the procedure shownin FIG. 4.

Case 2: The base station sends, by using the dedicated signaling, arandom access parameter set corresponding to a plurality of logicalchannels or logical channel groups. In this case, the terminal mayselect one corresponding random access parameter set based on a logicalchannel or logical channel group used for to-be-sent uplink data and/orsignaling. After the terminal selects a random access parameter set, arandom access process performed based on the random access parameter setis similar to a corresponding part of the procedure shown in FIG. 4. The“random access group” described in S402 to S405 may be replaced with the“logical channel or logical channel group”.

For example, before sending an Msg1 message, the terminal may determinea corresponding random access parameter set based on the logical channelor logical channel group used for the to-be-sent uplink data and/orsignaling. The terminal sends the Msg1 based on a random access preamblesequence in the random access parameter set and a time-frequencyresource of the preamble sequence. Further, the terminal may start arandom access response time window based on monitoring start time and/ora time window size of the random access response time window in therandom access parameter set, and listen to, within the time window, theMsg2 returned by the base station.

After receiving the Msg1, the base station may determine a correspondinglogical channel or logical channel group based on a random accesspreamble sequence sent by the terminal and/or a time-frequency resourceoccupied by the sequence, allocate an uplink resource to the terminalbased on an Msg3 size threshold value corresponding to the logicalchannel or logical channel group, add indication information of theuplink resource to the Msg2, and return the Msg2 to the terminal.

For another example, the base station may add a plurality of randombackoff indicators corresponding to a plurality of logical channels orlogical channel groups to the Msg2, and return the Msg2 to the terminal.One or more logical channels or logical channel groups correspond to onerandom backoff indicator. A MAC CE format in the Msg2 may be shown inFIG. 5. In another embodiment, the MAC CE in the Msg2 carries one randombackoff indicator. A random backoff indicator (random backoff time)corresponding to each random access logical channel or logical channelgroup may be obtained through calculation in the following manner: usingthe random backoff indicator included in the MAC CE as a referencevalue, and multiplying a random access time coefficient corresponding tothe random access logical channel or logical channel group, to obtainthe random backoff time corresponding to the random access logicalchannel or logical channel group. A value range of the random accesstime coefficient may be set to (0, 1), in other words, the random accesstime coefficient is greater than 0 and less than 1.

Case 3: The base station sends a random access parameter set by usingthe dedicated signaling. In this case, the terminal initiates a randomaccess process based on the random access parameter set. The randomaccess process is similar to a corresponding part of the procedure shownin FIG. 4. A difference lies in that there is only one parameter setused by the terminal in a connected mode or an inactive mode to performrandom access, so that neither the base station nor the terminal needsto perform a selection operation of the random access parameter set.

It may be learned from the foregoing descriptions that, in thisembodiment of this application, the base station may send a plurality ofrandom access parameter sets to the terminal. When performing randomaccess, the terminal may perform random access based on one of theplurality of random access parameter sets, and may performdifferentiated random access processes in different scenarios.

Based on a same technical conception, an embodiment of this applicationfurther provides a base station. FIG. 7 shows an example of a structureof the base station. The base station may perform the proceduresimplemented on a base station side in the procedures shown in FIG. 3 andFIG. 4. The base station may include a sending module 701 and areceiving module 702. The sending module 701 may be a transmitter,configured to send information. The receiving module 702 may be areceiver, configured to receive information. In an example, the sendingmodule 701 may be a wireless signal transmitter, configured to send awireless signal, and the receiving module 702 may be a wireless signaltransmitter, configured to transmit a wireless signal. Further, thesending module 701 and the receiving module 702 may be connected to aprocessor (not shown in the figure). The receiving module may sendreceived information to the processor for processing, and the sendingmodule may send the information processed by the processor.

The sending module 701 is configured to send a plurality of randomaccess parameter sets to a terminal by using a broadcast message. Thereceiving module 702 is configured to receive a random access request ofthe terminal. One of the plurality of random access parameter sets isused in the random access request.

Optionally, the plurality of random access parameter sets are aplurality of random access parameter sets corresponding to a pluralityof random access groups, and one or more random access groups correspondto one random access parameter set.

Optionally, the plurality of random access parameter sets include arandom access parameter set corresponding to a default random accessgroup.

Optionally, the random access parameter set further includes a randomaccess preamble sequence. The random access request includes the randomaccess preamble sequence. The sending module 701 is further configuredto: after the receiving module 702 receives the random access requestsent by the terminal, return a random access response message to theterminal. The random access response message includes indicationinformation of an uplink resource allocated to the terminal. The uplinkresource is allocated by the base station based on a scheduling messagesize threshold value corresponding to a random access group. The randomaccess group is a random access group corresponding to the random accesspreamble sequence sent by the terminal.

Optionally, the sending module 701 is further configured to: after thereceiving module 702 receives the random access request sent by theterminal, return a random access response to the terminal. The randomaccess response includes a plurality of random backoff indicatorscorresponding to the plurality of random access groups.

Based on a same technical conception, an embodiment of this applicationfurther provides a base station. FIG. 8 shows an example of a structureof the base station. The base station may perform the procedureimplemented on a base station side in the procedure shown in FIG. 6. Thebase station may include a sending module 801 and a receiving module802. The sending module 801 may be a transmitter, configured to sendinformation. The receiving module 802 may be a receiver, configured toreceive information. In an example, the sending module 801 may be awireless signal transmitter, configured to send a wireless signal, andthe receiving module 802 may be a wireless signal transmitter,configured to transmit a wireless signal. Further, the sending module801 and the receiving module 802 may be connected to a processor (notshown in the figure). The receiving module may send received informationto the processor for processing, and the sending module may send theinformation processed by the processor.

The sending module 801 is configured to send, by using dedicatedsignaling, at least one random access parameter set to a terminal in aconnected mode or an inactive mode. The receiving module 802 isconfigured to receive a random access request of the terminal in aconnected mode or an inactive mode. One of the at least one randomaccess parameter set is used in the random access request. The randomaccess parameter set includes monitoring start time and/or a time windowsize of a random access response time window.

Optionally, the random access parameter set further includes a randomaccess preamble sequence. The random access request includes the randomaccess preamble sequence. The sending module 801 is further configuredto: after the receiving module 802 receives the random access requestsent by the terminal in a connected mode or an inactive mode, return arandom access response to the terminal. The random access responseincludes indication information of an uplink resource allocated to theterminal. The uplink resource is allocated by the base station based ona scheduling message size threshold value corresponding to a randomaccess group. The random access group is a random access groupcorresponding to the random access preamble sequence sent by theterminal.

Optionally, the sending module 801 is further configured to: after thereceiving module receives the random access request of the terminal in aconnected mode or an inactive mode, return the random access response tothe terminal, where the random access response includes a plurality ofrandom backoff indicators corresponding to a plurality of random accessgroups, logical channels, or logical channel groups.

Optionally, the at least one random access parameter set is one randomaccess parameter set. Alternatively, the at least one random accessparameter set is a plurality of random access parameter setscorresponding to a plurality of random access groups. One or more randomaccess groups correspond to one random access parameter set.Alternatively, the at least one random access parameter set is a randomaccess parameter set corresponding to a plurality of logical channels orlogical channel groups. One or more logical channels or logical channelgroups correspond to one random access parameter set.

Optionally, the random access parameter set further includes one or anycombination of the following parameters:

indication information of a random access preamble sequence;

indication information of a time-frequency resource occupied by therandom access preamble sequence;

a timing time length of a contention resolution timer; and

a maximum quantity of random access times.

Based on a same technical conception, an embodiment of this applicationfurther provides a terminal. FIG. 9 shows an example of a structure ofthe terminal. The terminal may perform the procedures implemented on aterminal side in the procedures shown in FIG. 3 and FIG. 4. The terminalmay include a receiving module 901 and a sending module 902. The sendingmodule 902 may be a transmitter, configured to send information. Thereceiving module 901 may be a receiver, configured to receiveinformation. In an example, the sending module 902 may be a wirelesssignal transmitter, configured to send a wireless signal, and thereceiving module 901 may be a wireless signal transmitter, configured totransmit a wireless signal. Further, the sending module 902 and thereceiving module 901 may be connected to a processor (not shown in thefigure). The receiving module may send received information to theprocessor for processing, and the sending module may send theinformation processed by the processor.

The receiving module 901 is configured to receive a plurality of randomaccess parameter sets sent by a base station by using a broadcastmessage. The sending module 902 is configured to send a random accessrequest to the base station by using one of the plurality of randomaccess parameter sets.

Optionally, the plurality of random access parameter sets are aplurality of random access parameter sets corresponding to a pluralityof random access groups, and one or more random access groups correspondto one random access parameter set.

Optionally, the plurality of random access parameter sets include arandom access parameter set corresponding to a default random accessgroup.

Optionally, the terminal further includes a determining module (notshown in the figure). The determining module may alternatively bereplaced with a processor. The receiving module 901 is furtherconfigured to: after the sending module 902 sends the random accessrequest to the base station, receive a random access response returnedby the base station. The random access response includes a plurality ofrandom backoff indicators corresponding to the plurality of randomaccess groups. The determining module is configured to: determine acorresponding random access group based on a random access event, andselect, based on the determined random access group, a correspondingrandom backoff indicator from the plurality of random backoff indicatorscorresponding to the plurality of random access groups.

Based on a same technical conception, an embodiment of this applicationfurther provides a terminal. FIG. 10 shows an example of a structure ofthe terminal. The terminal may perform the procedure implemented on aterminal side in the procedure shown in FIG. 6. The terminal may includea receiving module 1001 and a sending module 1002. The sending module1002 may be a transmitter, configured to send information. The receivingmodule 1001 may be a receiver, configured to receive information. In anexample, the sending module 1002 may be a wireless signal transmitter,configured to send a wireless signal, and the receiving module 1001 maybe a wireless signal transmitter, configured to transmit a wirelesssignal. Further, the sending module 1002 and the receiving module 1001may be connected to a processor (not shown in the figure). The receivingmodule may send received information to the processor for processing,and the sending module may send the information processed by theprocessor.

The sending module 1002 is configured to: when the terminal is in aconnected mode or an inactive mode, receive at least one random accessparameter set sent by a base station by using dedicated signaling. Thesending module 1002 is configured to: when the terminal is in aconnected mode or an inactive mode, send a random access request to thebase station by using one of the at least one random access parameterset. The random access parameter set includes monitoring start timeand/or a time window size of a random access response time window.

Optionally, the terminal further includes a determining module (notshown in the figure). The determining module may alternatively bereplaced with a processor. The random access parameter set furtherincludes a random access preamble sequence. The random access requestincludes the random access preamble sequence. The determining module isconfigured to determine a corresponding random access parameter setbased on a logical channel or a logical channel group used forto-be-sent uplink data and/or signaling. The sending module isspecifically configured to send the random access preamble sequence inthe random access parameter set to the base station based on thedetermined random access parameter set.

Optionally, the terminal further includes a determining module (notshown in the figure). The determining module may alternatively bereplaced with a processor. The receiving module is further configuredto: after the sending module sends the random access request to the basestation, receive a random access response returned by the base station.The random access response includes a plurality of random backoffindicators corresponding to the plurality of random access groups,logical channels, or logical channel groups. The determining module isconfigured to: determine a corresponding random access group, logicalchannel, or logical channel group based on a random access event, andselect a corresponding random backoff indicator from the plurality ofrandom backoff indicators based on the determined random access group,logical channel, or logical channel group.

Optionally, the at least one random access parameter set is one randomaccess parameter set. Alternatively, the at least one random accessparameter set is a plurality of random access parameter setscorresponding to a plurality of random access groups. One or more randomaccess groups correspond to one random access parameter set. Theplurality of random access groups correspond to a public land mobilenetwork PLMN accessed by the terminal in a connected mode or an inactivemode. Alternatively, the at least one random access parameter set is arandom access parameter set corresponding to a plurality of logicalchannels or logical channel groups. One or more logical channels orlogical channel groups correspond to one random access parameter set.

Optionally, the random access parameter set further includes one or anycombination of the following parameters:

indication information of a random access preamble sequence;

indication information of a time-frequency resource occupied by therandom access preamble sequence;

a timing time length of a contention resolution timer; and

a maximum quantity of random access times.

Based on a same technical conception, an embodiment of this applicationfurther provides a base station. FIG. 11 shows an example of a structureof the base station.

As shown in FIG. 11, the network element includes a communicationsinterface 1101, a processor 1102, and a memory 1103. The memory 1103 isconfigured to store program code that needs to be executed by theprocessor 1102. The communications interface 1101 performs messageexchange. The processor 1102 is configured to execute the program codestored in the memory, and is specifically configured to perform themethod performed on the base station side in the foregoing embodiment.

The processor 1102 may be a central processing module (centralprocessing unit, CPU for short), a digital processing module, or thelike. The memory 1103 may be a non-volatile memory such as a hard diskdrive (hard disk drive, HDD for short) or a solid-state drive(solid-state drive, SSD for short), or may be a volatile memory(volatile memory) such as a random-access memory (random-access memory,RAM for short). The memory 1103 is any other medium that can be used tocarry or store desired program code in a form of an instruction or adata structure and that can be accessed by a computer, but is notlimited thereto.

In this embodiment of this application, a specific connection mediumamong the communications interface 1101, the processor 1102, and thememory 1103 is not limited. In this embodiment of this application, thememory 1103, the processor 1102, and the communications interface 1101are connected by using a bus 1104 in FIG. 11. The bus is represented byusing a thick line in FIG. 11. A manner of connection between othercomponents is merely an example for description, and imposes nolimitation. The bus may be classified into an address bus, a data bus, acontrol bus, and the like. For ease of representation, only one thickline is used to represent the bus in FIG. 11, but this does not meanthat there is only one bus or only one type of bus.

Based on a same technical conception, an embodiment of this applicationfurther provides a terminal. FIG. 12 shows an example of a structure ofthe terminal.

As shown in FIG. 12, the network element includes a communicationsinterface 1201, a processor 1202, and a memory 1203. The memory 1203 isconfigured to store program code that needs to be executed by theprocessor 1202. The communications interface 1201 performs messageexchange. The processor 1202 is configured to execute the program codestored in the memory, and is specifically configured to perform themethod performed on the terminal side in the foregoing embodiment.

The processor 1202 may be a central processing module (centralprocessing unit, CPU for short), a digital processing module, or thelike. The memory 1203 may be a non-volatile memory such as a hard diskdrive (hard disk drive, HDD for short) or a solid-state drive(solid-state drive, SSD for short), or may be a volatile memory(volatile memory) such as a random-access memory (random-access memory,RAM for short). The memory 1203 is any other medium that can be used tocarry or store desired program code in a form of an instruction or adata structure and that can be accessed by a computer, but is notlimited thereto.

In this embodiment of this application, a specific connection mediumamong the communications interface 1201, the processor 1202, and thememory 1203 is not limited. In this embodiment of this application, thememory 1203, the processor 1202, and the communications interface 1201are connected by using a bus 1204 in FIG. 12. The bus is represented byusing a thick line in FIG. 12. A manner of connection between othercomponents is merely an example for description, and imposes nolimitation. The bus may be classified into an address bus, a data bus, acontrol bus, and the like. For ease of representation, only one thickline is used to represent the bus in FIG. 12, but this does not meanthat there is only one bus or only one type of bus.

An embodiment of the present invention further provides a computerreadable storage medium, configured to store a computer softwareinstruction used to execute operations that need to be executed by theprocessor. The computer software instruction includes a program used toexecute the operations that need to be executed by the processor.

A person skilled in the art should understand that the embodiments ofthis application may be provided as a method, a system, or a computerprogram product. Therefore, this application may use a form of hardwareonly embodiments, software only embodiments, or embodiments with acombination of software and hardware. Moreover, this application may usea form of a computer program product that is implemented on one or morecomputer-usable storage media (including but not limited to a diskmemory, a CD-ROM, an optical memory, and the like) that includecomputer-usable program code.

This application is described with reference to the flowcharts and/orblock diagrams of the method, the device (system), and the computerprogram product according to this application. It should be understoodthat computer program instructions may be used to implement each processand/or each block in the flowcharts and/or the block diagrams and acombination of a process and/or a block in the flowcharts and/or theblock diagrams. These computer program instructions may be provided fora general-purpose computer, a dedicated computer, an embedded processor,or a processor of any other programmable data processing device togenerate a machine, so that the instructions executed by a computer or aprocessor of any other programmable data processing device generate anapparatus for implementing a specific function in one or more processesin the flowcharts and/or in one or more blocks in the block diagrams.

These computer program instructions may be stored in a computer readablememory that can instruct the computer or any other programmable dataprocessing device to work in a specific manner, so that the instructionsstored in the computer readable memory generate an artifact thatincludes an instruction apparatus. The instruction apparatus implementsa specific function in one or more processes in the flowcharts and/or inone or more blocks in the block diagrams.

These computer program instructions may be loaded onto a computer oranother programmable data processing device, so that a series ofoperations and steps are performed on the computer or the anotherprogrammable device, thereby generating computer-implemented processing.Therefore, the instructions executed on the computer or the anotherprogrammable device provide steps for implementing a specific functionin one or more processes in the flowcharts and/or in one or more blocksin the block diagrams.

1. A communication method, comprising: receiving, by a terminal, atleast one random access parameter set from a base station; sending, bythe terminal, a random access request to the base station using onerandom access parameter set of the at least one random access parameterset; wherein one or more random access groups correspond to one randomaccess parameter set, and one random access group of the one or morerandom access groups corresponds to a network slice.
 2. Thecommunication method of claim 1, wherein the receiving, by a terminal,at least one random access parameter set from a base station, comprises:receiving, by the terminal, a plurality of random access parameter setssent from the base station using a broadcast message.
 3. Thecommunication method of claim 1, wherein the receiving, by a terminal,at least one random access parameter set from a base station, comprises:receiving, by the terminal, a plurality of random access parameter setssent from the base station using dedicated signaling.
 4. Thecommunication method of claim 1, wherein the one random access groupcorresponds to a random backoff time coefficient, the random backofftime coefficient is greater than 0 and less than 1, and a random backofftime corresponding to the one random access group is obtained throughcalculation in the following manner: using a random backoff indicatorincluded in a media access control-control element (MAC CE) as areference value, and multiplying a random access time coefficientcorresponding to the random access group.
 5. The method according toclaim 1, wherein the random access parameter set further comprises oneor any combination of the following parameters: indication informationof a random access preamble sequence; indication information of atime-frequency resource occupied by the random access preamble sequence;a timing time length of a contention resolution timer; a maximumquantity of random access times; and a scheduling message sizethreshold.
 6. A communication apparatus, comprising: at least oneprocessor, wherein the at least one processor is coupled to at least onememory storing programming instructions executable by the at least oneprocessor to perform operations comprising: receiving at least onerandom access parameter set from a base station; sending a random accessrequest to the base station using one random access parameter set of theat least one random access parameter set; wherein one or more randomaccess groups correspond to one random access parameter set, and onerandom access group of the one or more random access groups correspondsto a network slice.
 7. The communication apparatus according to claim 6,wherein the operations further comprises: receiving a plurality ofrandom access parameter sets sent from the base station using abroadcast message.
 8. The communication apparatus according to claim 6,wherein the operations further comprises: receiving a plurality ofrandom access parameter sets sent from the base station using dedicatedsignaling.
 9. The communication apparatus according to claim 6, whereinthe one random access group corresponds to a random backoff timecoefficient, the random backoff time coefficient is greater than 0 andless than 1, and a random backoff time corresponding to the one randomaccess group is obtained through calculation in the following manner:using the random backoff indicator included in a media accesscontrol-control element (MAC CE) as a reference value, and multiplying arandom access time coefficient corresponding to the random access group.10. The communication apparatus according to claim 6, wherein the randomaccess parameter set further comprises one or any combination of thefollowing parameters: indication information of a random access preamblesequence; indication information of a time-frequency resource occupiedby the random access preamble sequence; a timing time length of acontention resolution timer; a maximum quantity of random access times;and a scheduling message size threshold.
 11. A communication apparatus,comprising: at least one processor, wherein the at least one processoris coupled to at least one memory storing programming instructionsexecutable by the at least one processor to perform operationscomprising: sending at least one random access parameter set to aterminal; receiving a random access request from the terminal using onerandom access parameter set of the at least one random access parameterset; wherein one or more random access groups correspond to one randomaccess parameter set, and one random access group of the one or morerandom access groups corresponds to a network slice.
 12. Thecommunication apparatus according to claim 11, wherein the operationsfurther comprises: sending a plurality of random access parameter setsto the terminal using a broadcast message.
 13. The communicationapparatus according to claim 11, wherein the operations furthercomprises: sending a plurality of random access parameter sets to theterminal using dedicated signaling.
 14. The communication apparatusaccording to claim 11, wherein the one random access group correspondsto a random backoff time coefficient, the random backoff timecoefficient is greater than 0 and less than 1, and a random backoff timecorresponding to the one random access group is obtained throughcalculation in the following manner: using the random backoff indicatorincluded in a media access control-control element (MAC CE) as areference value, and multiplying a random access time coefficientcorresponding to the random access group.
 15. The communicationapparatus according to claim 11, wherein the random access parameter setfurther comprises one or any combination of the following parameters:indication information of a random access preamble sequence; indicationinformation of a time-frequency resource occupied by the random accesspreamble sequence; a timing time length of a contention resolutiontimer; a maximum quantity of random access times; and a schedulingmessage size threshold.